Coloboma
Coloboma is a congenital condition where normal tissue in or around the eye is missing. It's present from birth because it occurs when the eye develops in the womb during the first three months of growth.
A coloboma can be in one or both eyes (bilateral coloboma). There are different types of coloboma, depending on which part of the eye's structure is affected by abnormalities. The type of coloboma influences how much it affects vision.
Treatment for coloboma malformations depends on the type. For some, the focus will be on making the most of a child's vision, using visual aids and other adjustments.
A diagram of a healthy eye with labels.
A diagram of an eye with coloboma. The diagram shows the structures in the eye that can have missing tissue caused by this congenital condition. These include the iris, retina, choroid, and optic disc.
What causes coloboma?
Coloboma can develop without an identified cause or known family history of the condition. Most cases of coloboma appear to happen by chance.
However, causes of coloboma can include genetic factors, and it can be inherited in families with a history of the condition. There are also some genetic conditions associated with coloboma, for example, CHARGE syndrome and Treacher Collins syndrome.
Coloboma symptoms
Coloboma is often diagnosed in babies at their newborn screening check, especially if it's noticeable, for example, iris or eyelid coloboma. It's not always possible to predict the impact of coloboma on a child's vision until they're older, and it can vary depending on the type of coloboma.
Eyelid coloboma
This type of coloboma differs from the others described above, as it affects the outer eyelid, not the eye's internal structures. Signs and symptoms include:
- There may be a missing part of the upper or lower eyelid.
- It's usually noticeable and has a cosmetic effect on the appearance of the eye.
- Eyelid coloboma can cause increased sensitivity to light.
Coloboma treatments
Treatments for coloboma depend on the part of the eye that is affected.
Many children with iris coloboma do not need treatment. Wearing a special contact lens is an option if iris coloboma is noticeable cosmetically. This improves the appearance of the pupil and helps reduce light sensitivity. Sometimes, surgery is an option to sew together the gap and provide a more permanent solution.
Other types of coloboma cannot be corrected. The focus then is on supporting a child's visual development. Children with coloboma will have regular check-ups with a hospital eye specialist to monitor their vision as they grow and develop.
It's important to detect and manage other eye conditions to make the most of a child's eyesight with coloboma. Glasses can correct refractive errors such as near-sightedness, long-sightedness, and astigmatism. Amblyopia (lazy eye) is a possible complication of coloboma, so your child's eye specialist will be checking whether treatment for this is needed. Over time, other eye conditions can develop, some of which, such as cataracts, can be treated.
When to get medical advice
Regular eye tests can detect a range of eye conditions in both children and adults. Babies and children have their eyes checked at key milestones as they grow.
If you have concerns about your baby or toddler's sight, speak to your GP or health visitor for an ophthalmology referral. You can take your child to a high street optician for an eye test from around the age of three.
There's support available to help children and adults living with coloboma make the most of their vision.
Living with coloboma
People living with coloboma can have quite different experiences because its effect on vision can vary.
If your child is diagnosed with coloboma, it may not be possible to know at first how it will affect their vision. Your child's eye specialist will monitor them regularly. Getting support in the early years can help support your child as their vision develops.
Frequently asked questions
Medically reviewed by: The Royal College of Ophthalmologists on 18/10/2022
Edited by: Nick Astbury FRCS FRCOphth FRCP
Clinical Associate Professor
LSHTM
The Royal College of Ophthalmologists champions excellence in the practice of ophthalmology and is the only professional membership body for medically qualified ophthalmologists. The RCOphth is unable to offer direct advice to patients. If you’re concerned about the health of your eyes, you should seek medical advice from your GP, optometrist or ophthalmologist.